This invention relates to a magnetic disc drive having a plurality of magnetic heads.
Electronic still video cameras have been developed in which still color picture information resulting from photography is electrically recorded on a magnetic disc referred to as a still video floppy. Since the amount of image information recorded on the magnetic disc used in an electronic still video camera is small, resolution is poor when a camera output is reproduced as still picture. There are cases where such poor resolution cannot be accepted.
Accordingly, in order to increase the amount of image signal information, it has been contemplated to use an image pick-up element having a large number of pixels and to increase the number of video disc tracks per image. To this end, it has been proposed to provide a magnetic head having four magnetic gaps for four tracks on a magnetic disc in order to record on or playback these tracks simultaneously. However, a magnetic disc is rotated at a high speed of 3600 rpm. In order to maintain good contact between the magnetic gaps of the magnetic head and the recording surface of the magnetic disc during this high-speed rotation, it is required that a stabilizer formed to have an opening extending in the radial direction of the disc be disposed on the side of the disc opposite its recording surface, and that the magnetic disc be brought into contact with the magnetic head by this stabilizer.
On the other hand, the surface of the magnetic head is formed to be spherical in order to assure good contact between the magnetic head and the magnetic disc. When such a magnetic head is used, it is difficult to record or play back image information with just one magnetic head having four magnetic gaps by using the stabilizer.
More specifically, since the magnetic disc contacted by the head tends to flex, only a portion of the head contacts the magnetic disc recording surface and it is very difficult to bring all four of the magnetic gaps into uniform contact with the recording surface. As a result, it is substantially impossible to make inputs and outputs to and from the magnetic disc. Accordingly, an arrangement has been proposed in which, say, two magnetic heads each having two magnetic gaps are provided and spaced apart a predetermined distance and the aforementioned stabilizer is used to assure contact between the magnetic disc and each of the magnetic heads.
However, with this arrangement in which the stabilizer is provided for the two magnetic heads each having the two magnetic gaps, a problem that arises is that uniform contact cannot be achieved between each of the magnetic gaps and the magnetic disc. That is, when the surface of each magnetic head on which the magnetic gaps are disposed (namely the head top) is provided perpendicular to the magnetic disc recording surface, as in the case where there is a single magnetic head, the disc is caused to flex by the top of one magnetic head and this flexure affects the other magnetic head, as a result of which the two heads do not contact the recording surface uniformly. Consequently, inputs and outputs cannot be made without an inclination at the magnetic gaps of the two magnetic heads having the two magnetic gaps.